tomcat程序连接服务器mysql数据库，报

错误，后来用java程序直接连接数据库，发现可以连得上，可以操作数据库，

在网上查了设置数据库连接等待时间(wait_timeout)设置，也没用。

奇怪的一点是，尽管控制台报错，但是还可以实现本人写的那个查询功能，可以从数据库中查到数据显示到页面

org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.)

at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:855)

at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:540)

at org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider.getConnection(LocalDataSourceConnectionProvider.java:81)

at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:72)

at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:1881)

at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1174)

at org.springframework.orm.hibernate3.LocalSessionFactoryBean.newSessionFactory(LocalSessionFactoryBean.java:805)

at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:745)

at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:134)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1175)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1145)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:427)

at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:251)

at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:144)

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:248)

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:160)

at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:261)

at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:109)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1073)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:835)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:423)

at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:251)

at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:144)

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:248)

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:160)

at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:279)

at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:360)

at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:241)

at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:184)

at com.base.common.spring.SpringContextLoaderServlet.init(SpringContextLoaderServlet.java:23)

at javax.servlet.GenericServlet.init(GenericServlet.java:158)

at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1284)

at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1197)

at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1087)

at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5262)

at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5550)

at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)

at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)

at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)

at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:649)

at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1245)

at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1895)

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)

at java.util.concurrent.FutureTask.run(FutureTask.java:262)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

at java.lang.Thread.run(Thread.java:745)

Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:526)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)

at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1118)

at com.mysql.jdbc.MysqlIO.(MysqlIO.java:343)

at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2308)

at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2122)

at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:774)

at com.mysql.jdbc.JDBC4Connection.(JDBC4Connection.java:49)

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:526)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)

at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:375)

at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:289)

at org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:37)

at org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:290)

at org.apache.commons.dbcp.BasicDataSource.validateConnectionFactory(BasicDataSource.java:877)

at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:851)

… 46 more

Caused by: java.net.ConnectException: Connection refused: connect

at java.net.DualStackPlainSocketImpl.connect0(Native Method)

at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)

at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)

at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)

at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)

at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)

at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)

at java.net.Socket.connect(Socket.java:579)

at java.net.Socket.connect(Socket.java:528)

at java.net.Socket.(Socket.java:425)

at java.net.Socket.(Socket.java:241)

at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)

at com.mysql.jdbc.MysqlIO.(MysqlIO.java:292)

… 61 more

解决方案

20

Caused by: java.net.ConnectException: Connection refused: connect

这个是数据库拒绝连接，可能是数据库服务器达到了最大连接数

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

答：可能是数据库回收了连接，缓冲池不知道，继续使用被回收的连接所致的。可以在jdbc字符串中增加&autoReconnect=true

奇怪的一点是，尽管控制台报错，但是还可以实现本人写的那个查询功能，可以从数据库中查到数据显示到页面

答：hibernate的缓存

20

jdbc字符串中增加&autoReconnect=true

哪个文件中写了jdbc，那里就加上

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